PS version definition and detailed classification

With the development of China's printing industry, China's printing industry has become the fastest growing market in the world. At present, China's per capita publishing consumption is about 40 US dollars, and there is still a big gap compared with developed countries. This shows that the prospects of the printing industry in China are very large. With the rapid development of China's economy, the average consumption level of publications per capita will increase greatly. China's PS industry also faces two challenges. One is the rapid rise and promotion of CTP technology. The second is that after China's accession to the WTO, due to the reduction of import tariffs on the PS version, the foreign premium PS version is now available on the existing domestic plate market. The impact came.

PS version definition

PS version is the abbreviation of Presensitized Offset Plates. Chinese means pre-coated photosensitive plate, which is developed to meet the rapid development of offset printing. Because the PS version has high resolution, full dot reproduction, rich layers, balanced ink and easy to handle, and high resistance to printing, it has rapidly gained popularity in the printing industry. Judging from the statistical data currently available, the PS version is still the largest consumer and most important plate material. The PS plate manufacturing industry has become one of the most important pillar industries in the printing equipment manufacturing industry.

In 1950, it was first developed by the Minisota Mining & Manufacturing Company. PS version is divided into "photopolymerization type" and "photolytic type" two. The photopolymerization type is used to print the original negative plate, and the photoreactive film of the diazo film in the graphic part is photohardened and remains on the plate. The non-graphical part of the diazo film does not see light, does not harden, and is dissolved and removed by the developer. The photodecomposition type was positively printed on the positive plate, and the diazo compound in the non-graphic part was photolyzed, dissolved and removed by the developer, and the diazo compound remaining on the plate was still not visible. The oleophilic part of the PS plate is a diazo photosensitive resin with a high publishing base plane of about 3 μm. It is a good hydrophobic film, and the ink is easily spread on it, but water is difficult to spread on it. Diazo photosensitive resin also has good abrasion resistance and acid resistance. If the film is baked at a temperature of 230 to 240° C. for 5 to 8 minutes and the photosensitive film is deuterated, the hardness of the printing plate can be improved, and the printing plate can withstand printing rates of up to 200,000 to 300,000 sheets. The hydrophilic part of the PS plate is an Al2O3 thin film. The high-printing substrate plane is about 0.2 to 1 μm. The hydrophilicity, abrasion resistance, and chemical stability are all relatively good. Therefore, the printing plate has a higher printing rate. PS version of the sand fine, high resolution, forming a smooth network of complete, it is good color reproduction, image clarity; PS version of the blank part has a higher moisture content, printing plate printing water consumption The ink balance is easy to control.

PS version classification

Variety and specifications

From the rapid development of CTP technology and equipment in recent years, the domestic demand for CTP plates is imminent. CTP plates have many varieties from the very beginning. Currently, common CTP plates include silver salt composite plates, silver salt diffusion transfer plates, thermal plates, photosensitive resin plates, and conventional forms of violet laser CTP plates (CTcP). Each type has a different laser wavelength range. Corresponding. In the conventional PS version, due to the improvement of the device performance and the different grades of the printed materials, different requirements will be put on the performance of the PS version. For example, newspaper printing is the most desirable printing plate with short printing time and high printing rate. Fine product printing requires high resolution of the photosensitive layer of the plate, good reproducibility of dots, and uniform flatness of large areas.

(D) PS version structure

The PS plate is a photosensitive offset plate having a multilayer structure. It uses an aluminum plate as a support and the aluminum plate undergoes a variety of processes. The purpose of these processes is to give it photographic properties and printability.

1. Mao Mian granules

Rough surface granules are an excellent plate material, it can improve the adhesion with the printing plate, shorten the vacuum time and reduce the halo phenomenon.

2 photosensitive layer

The different photosensitive layers will have a variety of different characteristics relative to different platemaking processes and the production process of each plate manufacturer.

3 hydrophilic layer

The photosensitive coating can be prevented from remaining in the pores of the anodic oxide layer.

Improve the hydrophilic properties of the plate to prevent dirt during the printing process.

4 Anodized layer

After the anodized aluminum substrate surface hardness increased, the chemical stability increased.

Increased abrasion resistance.

5 Sand structure

·Using the electrolytic roughening process to form a fine sand-mesh structure on the surface of the aluminum plate base so that the Huaguang PS plate has an ideal dot reproduction condition and good hydrophilicity.

· The sand grain structure of Huaguang PS plate is delicate and complex, which maximizes the contact surface between the printing plate and the fountain solution.

6 Aluminum plate support

Use aluminum plates suitable for PS plate process requirements, dimensional stability, high strength, and high purity (≥ 99.5%).